SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b543adb386c1c435f692d7e17aff4d64b2034aae3bb57999dc88d92d19564a41' 
  AND token = 'GnvfYGQf4/Hpk6tAov4NuaF2bltzK+xCtIEKOyXOUB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}